In a statement issued Monday she expresses "deep regret" she'll be unable to return in her recurring role "at this time." She'll appear in the season premiere, airing Sept. 30.
The 44-year-old actress was hit on the head by a piece of equipment while on the show's New York City set July 11. She was briefly hospitalized.
She says she's "getting better slowly."
Chenoweth won a Tony Award for her role in Broadway's "You're a Good Man, Charlie Brown" and an Emmy for her work on "Pushing Daisies." Last season she starred in the short-lived series "GCB."
